Ink rolls having a variety of structures, including microporous structures, have been known for some time. However, known ink rolls are not capable of dispensing a high contrast ink with sufficient sharpness and clarity so that the resulting print can be consistently read using a light scanner, such as a laser scanning device. A laser scanning device only detects sharp images with a high degree of contrast. Known ink rolls leave fuzzy images which cannot be consistently read by a laser scanning device.
The industry in consumer products and other high volume products has been converting to bar codes, such as Interleave 2 of 5, Code 3 of 9, or the Universal Products Code (UPC), for a variety of purposes, including warehousing and inventory control. This has lead to the affixing of bar codes to the outside of shipping cartons. In the past, this has been done by a variety of expensive methods, including pre-printed labels, or cartons pre-printed with the appropriate bar code. This, of course, leads to problems with inventory control and adds additional items of inventory for the manufacturer.
Using the ink rollers and methods of the present invention, simple line printing devices can be used to print a laser-scannable code such as a UPC Code on cartons and other packages in a fast and efficient manner. These codes can be printed with a read rate of approaching 99%, i.e., out of 100 prints made, at least 99 are readable by a laser scanning device.